Inverter transformer

Abstract

An inverter transformer is provided which can turn on a plurality of cold cathode fluorescent lamps (CFLs) with a minimized increase in the number of components, thereby reducing costs. The inverter transformer comprises a plurality of bobbins for windings. The plurality of bobbins each having a secondary winding wound thereon and having a bar-shaped inner core inserted therein are connected to one another for integration, and a primary winding is wound in common on the bobbins connected together. A plurality of inner cores and a rectangular frame-shaped outer core are magnetically coupled with each other with non-magnetic sheets interposed therebetween to provide a predetermined leakage inductance. A plurality of CFLs can be turned on with only one outer core, thereby reducing the number of components, downsizing the device, and reducing the cost.

What is claimed is:  
     
       1. An inverter transformer provided in a DC to AC inverter circuit and adapted to step up an AC voltage inputted to a primary side thereof and to output to a secondary side, comprising: 
       an outer core shaped substantially like a rectangular frame;  
       a plurality of inner cores shaped substantially like a bar, disposed inside the outer core and connected thereto so as to provide a predetermined leakage inductance;  
       a plurality of secondary windings provided corresponding to the plurality of inner cores;  
       a primary winding common to the plurality of secondary windings; and  
       a plurality of bobbins shaped substantially like a tube, provided corresponding to the plurality of secondary windings, each of the bobbins including a primary-side terminal block for the primary winding at one end thereof and a secondary-side terminal block for each of the secondary windings at the other end thereof, having each of the inner cores inserted therein, and having each of the secondary windings wound thereon, and the plurality of bobbins, with respective secondary windings wound thereon, being connected together for integration, and having the primary winding wound thereon.  
     
     
       2. An inverter transformer according to  claim 1 , wherein the plurality of bobbins are integrated such that respective primary-side terminal blocks each having a projection and a groove at a connecting portion are connected to one another and respective secondary-side terminal blocks each having a projection and a groove at a connecting portion are connected to one another. 
     
     
       3. An inverter transformer according to  claim 1 , wherein the outer core is provided with grooves for engaging with part of the primary-side and secondary-side terminal blocks of the plurality of bobbins integrated. 
     
     
       4. An inverter transformer according to  claim 1 , wherein the primary-side and secondary-side terminal blocks of the plurality of bobbins are provided with projections for engaging either with grooves formed on the outer core or with outside portions of the outer core. 
     
     
       5. An inverter transformer according to  claim 1 , wherein the pluarlity of inner cores are shaped substantially like an L. 
     
     
       6. An inverter transformer according to  claim 1 , wherein the plurality of bobbins are shaped identical with one another. 
     
     
       7. An inverter transformer according to  claim 2 , wherein the outer core is provided with grooves for engaging with part of the primary-side and secondary-side terminal blocks of the plurality of bobbins integrated. 
     
     
       8. An inverter transformer according to  claim 2 , wherein the primary-side and secondary-side terminal blocks of the plurality of bobbins are provided with projections for engaging either with grooves formed on the outer core or with outside portions of the outer core. 
     
     
       9. An inverter transformer according to  claim 3 , wherein the primary-side and secondary-side terminal blocks of the plurality of bobbins are provided with projections for engaging either with grooves formed on the outer core or with outside portions of the outer core. 
     
     
       10. An inverter transformer according to  claim 2 , wherein the plurality of inner cores are shaped substantially like an L. 
     
     
       11. An inverter transformer according to  claim 3 , wherein the plurality of inner cores are shaped substantially like an L. 
     
     
       12. An inverter transformer according to  claim 4 , wherein the plurality of inner cores are shaped substantially like an L. 
     
     
       13. An inverter transformer according to  claim 2 , wherein the plurality of bobbins are shaped identical with one another. 
     
     
       14. An inverter transformer according to  claim 3 , wherein the plurality of bobbins are shaped identical with one another. 
     
     
       15. An inverter transformer according to  claim 4 , wherein the plurality of bobbins are shaped identical with one another. 
     
     
       16. An inverter transformer according to  claim 5 , wherein the plurality of bobbins are shaped identical with one another.